| 摘要 |
PURPOSE:To prevent incorrect use of software by providing a program ciphered and recorded on a magnetic recording medium and a deciphering section decoding a cipher in pairs with the program and possible for removal. CONSTITUTION:A ciphered program, a non-ciphered program and data are recorded on a magnetic recording medium 5, a corresponding cipher decoding section 1 is fitted to a processing section 3 in operating the software to start the program. An FF 4 is set at this point of time, the program is decoded through the decoding section 1, expanded to a main storage section 2 via a selector 6 and executed by the processing section 3. The FF 4 is reset depending on any of the program end and removal of the decoding section 1 and the processing 3 is actuated by the set state only of the FF 4. Further, the FF 4 disables the removal of the decoding section 1 while the ciphered program is executed. |
